Earthquake forecasting

One year on from the magnitude-9.0 earthquake that unleashed a devastating tsunami and caused a partial meltdown of the Fukushima Daiichi nuclear plant, this month’s special issue of Physics World, on the theme of “Physics and the Earth”, includes an investigation by journalist Edwin Cartlidge into the latest advances in earthquake forecasting.

In addition to the special issue, physicsworld.com hosts an exclusive video documentary reviewing the fundamental science behind earthquakes and assessing the current efforts that are being made around the world to forecast these events. The video can be viewed on Physics World.

The huge responsibility that comes with assessing the likelihood of earthquakes was never more evident than in March 2009, when a group of 11 Italian scientists met to discuss the risk of a powerful earthquake striking the town of L’Aquila, after a swarm of small quakes had hit the area continuously for four months.

After concluding that there were no grounds for alarm, a devastating magnitude-6.3 earthquake struck the town on 6 April that year, leaving 308 people dead. Now, seven of those 11 scientists are on trial for manslaughter.

Thomas Jordan, chairman of the International Commission on Earthquake Forecasting (ICEF), argues in Physics World that the tragedy at L’Aquila highlights how vital it is for us to understand which are the most reliable types of forecasting, so that we have the best possible information at our fingertips.

Finding specific, natural events that may flag up an impending earthquake has been given a lot of thought; for example, a long-standing idea is that animals flee a specific area after somehow sensing an upcoming quake.

These precursors are unconvincing, however; and while we are unlikely to ever be able to predict precisely when, where and with what magnitude particular earthquakes will strike, much can be gained from short-term "probabilistic" forecasting, which can give the odds that an earthquake above a certain size will occur within a given area and time.

Still, these short-term “probabilistic” methods have their limitations, as was demonstrated a year ago this month when even the most up-to-date models did not predict the Japanese earthquake.

“This approach is tricky because no-one can quite agree on which are the best models. So, we have uncertainty on uncertainty. But can we ignore the information that they give us? The earthquakes in L’Aquila and New Zealand taught us we don’t have that luxury,” says Jordan.

Also in this issue

Lessons from Fukushima -- Mike Weightman, UK's chief inspector of nuclear installations -- discusses what we can learn from last year's nuclear incident

Physics and fracking -- journalist Jon Cartwright examines how physicists can help assess the controversial process of releasing gas from shale by pumping sand and chemicals in at high pressures

The Earth from afar -- a set of stunning images of our planet produced using a range of visualization techniques

Prospecting with geoneutrinos -- how tiny almost massless neutrinos, generated from radioactive decay deep within the Earth, could shed light on the interior of our planet

When north moves south -- could the movement of tectonic plates explain the variation in the rate of reversal of the Earth's magnetic field?

A pressing matter -- studies of the conditions deep inside our planet suggest that its core may contain immense crystals of iron up to 10 km long

The special issue of Physics World can be downloaded as a PDF, free of charge, from Thursday 8 March. Members can access the special issue now at physicsworld.com